Electroreflectance measurements of electric fields in ordered GaInP2

Abstract

Ordered Ga0.52In0.48P alloys (GaInP2 for simplicity) grown on miscut [001] GaAs resemble monolayer superlattices with alternating Ga- and In-rich layers along either the [1̄11] or [11̄1] directions. Recent calculations suggest that, in fully ordered GaInP2, an intrinsic ordering-induced electric field of order 1600 kV/cm should exist. In partially ordered samples, as can actually be grown, the expected field is reduced to 400 kV/cm. For such a strong internal electric field, clear Franz–Keldysh Oscillations (FKOs) would be expected in an electroreflectance measurement. We report electroreflectance measurements of ordered GaInP2 layers measured at T=100 K. For all samples measured, no FKOs are observed in the absence of an additional external dc bias voltage. At the lowest bias voltages for which FKOs are seen, the internal electric field in the GaInP2 layer, determined from the FKOs, is ∼60 kV/cm along the [001] direction corresponding to ∼100 kV/cm along the ordering direction. Hence, we conclude that, at least in the organometallic vapor phase epitaxy grown samples studied here, any net macroscopic internal electric field in the GaInP2 layer is less than ∼100 kV/cm along the ordering direction.

Determination Of Piezo-Electric Fields In Spontaneously Ordered InGaAsP

“…Both theoretical and experimental papers on ordering induced piezo-electric fields in ternary III-V compound semiconductors [1,2,3] are not able to give a clear evidence for, nor against the existence of piezo-electric fields. In principle, such a field could exist because of the symmetry change of the crystal from ZnS (where a piezo-electric field is not possible due to inversion symmetry) to CuPt B (where piezo-electric fields could in principle establish).…”

Temperature dependence of electroreflectance spectroscopy in Ga0.5In0.5P alloy

“…Modulation spectroscopy is a popular means of analysing critical point (CP) structures in semiconductors [3]. Some modulation techniques, such as electroreflectance (ER) [4][5][6][7][8][9][10], photoreflectance (PR) [11,12], electroabsorption [13], piezoreflectance (PzR) [14,15] and thermoreflectance (TR) [16], have been used to investigate CP structures in Ga 0.5 In 0.5 P and consequently, its electronic band structure. The temperature dependence of the E 0 /(E 0 + 0 ) energies for Ga 0.5 In 0.5 P has also been extensively investigated using various techniques, such as ER [6], PR [11], PzR [15], photoluminescence [6,[17][18][19][20][21] and photoluminescence excitation spectroscopy [18,21].…”

Improved photoluminescence characteristics of order-disorder AlGaInP quantum wells at room and elevated temperatures

“…8 While such an increase in peakemission was indeed recorded in the ordered x ¼ 0.4 sample at 30 K (a peak-shift of 12 meV/decade), no change in emission energy at room-temperature was detected with increasing excitation, possibly due to the complete screening of this field by the background doping. 29 Thus, further experiments are necessary to unequivocally identify the cause for the longer recombination lifetime in the ordered quantum-well. However, in contrast to reported low-temperature measurements, the room-temperature recombination dynamics of ordered quantum-wells begin to approach that of the disordered quantum-well.…”